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Abstract:

Manufacturing a coated substrate by magnetron sputtering includes
cyclically moving the magnetron magnetic field pattern along a sputter
surface, positioning a substrate to be coated a distance from and facing
the sputter surface, moving the substrate along the sputter surface and
varying an amount of material deposited on the total substrate per time
unit from the magnetron source that is cyclically and phase-locked with
the cyclically moving magnetron magnetic field pattern.

Claims:

1. A method for manufacturing a coated substrate by magnetron sputtering
comprising:a) providing a magnetron source with a sputter surface, the
magnetron source generating a magnetron magnetic field pattern along the
sputter surface;b) cyclically moving said magnetron magnetic field
pattern along said sputter surface;c) positioning a substrate to be
coated a distance from and facing said sputter surface;d) moving said
substrate along said sputter surface; ande) varying an amount of material
deposited on said total substrate per time unit from said magnetron
source that is cyclically and phase-locked with said cyclically moving
said magnetron magnetic field pattern.

2. The method of claim 1, further comprising cyclically moving said
magnetron magnetic field pattern in two dimensions.

3. The method of claim 1, further comprising cyclically moving said
magnetron magnetic field in at least one of a rotational pendular manner
and a rotational manner with respect to an axis perpendicular to said
sputter surface.

4. The method of claim 1, further comprising cyclically varying said
amount of material simultaneously along the entire sputter surface.

5. The method of claim 1, further comprising varying said amount of
material by varying at least one of a flow of a reactive gas and a flow
of a working gas into an area between said sputter surface and said
substrate.

6. The method of claim 1, further comprising varying said amount of
material by controlling a power applied to said magnetron source.

7. The method of claim 1, further comprising varying said amount of
material with a time course having a frequency spectrum with a
significant spectral line at a double frequency of a fundamental
frequency of cyclically moving said magnetron magnetic field pattern.

8. The method of claim 7, wherein said time course has a further
significant spectral line at the fundamental frequency of cyclically
moving said magnetron magnetic field pattern.

9. The method of claim 1, further comprising tailoring said magnetron
magnetic field pattern symmetrically to an axis in a plane which is
parallel to said sputter surface.

10. The method of claim 1, further comprising tailoring said magnetron
magnetic field pattern symmetrically with respect to two mutually
perpendicular axes in a plane which is parallel to said sputter surface.

11. The method of claim 1, further comprising applying a reactive gas into
an area between said sputter surface and said substrate.

13. The method of claim 1, further comprising not influencing a material
flow distribution from said sputter surface to said substrate.

14. The method of claim 1, further comprising selecting a time course of
varying said amount of material with respect to at least one of a
relative movement between the substrate and the sputter surface, a shape
ofsaid magnetron magnetic field pattern, and a movement course of said
magnetron magnetic field pattern.

15. The method of claim 1, further comprising time varying a course of
varying said amount of material.

16. The method of claim 1, further comprising monitoring a distribution of
material momentarily deposited on said substrate, comparing said
monitored distribution with a desired distribution, and adjusting
characteristics of varying said amount of material as a function of a
difference between said desired distribution and said monitored
distribution in a negative feedback control loop.

17. The method of claim 1, further comprising repeatedly moving said
substrate along said sputter surface.

18. The method of claim 1, further comprising cyclically moving said
substrate along said sputter surface in at least one of a single
direction motion and a forth and back motion.

19. The method of claim 1, further comprising moving said substrate along
said sputter surface linearly as considered in a view towards said
sputter surface.

20. The method of claim 1, further comprising moving said substrate within
a plane parallel to said sputter surface.

21. The method of claim 1, further comprising moving said substrate along
a non-linear trajectory path as considered in a view parallel to said
sputter surface.

22. The method of claim 1, further comprising moving said substrate along
a non-linear path as considered in a view onto said sputter surface.

23. The method of claim 1, further comprising moving said substrate along
a circular trajectory path as considered in a view towards said sputter
surface about a center remote from said sputter surface.

24. The method of claim 1, further comprising superposing to said varying
of said amount of material a further varying of said amount synchronized
with said moving of said substrate.

25. The method of claim 1, wherein an optimized homogeneous coating
thickness distribution is achieved on said substrate.

26. The method of claim 1, wherein an optimized homogeneous distribution
of material stoichiometry is achieved along the coating of said
substrate.

27. The method of claim 1, wherein the method of magnetron sputtering
comprises a method of coating planar substrates.

28. The method of claim 1, wherein said coated substrate has a coating
thickness deviation from an average coating thickness value which is less
than or equal to 1% considered along a substrate surface that is greater
than 1,000 cm.sup.2.

29. The method of claim 1, wherein said coated substrate has a local
deviation of deposited amount of material of at most 0.01% with respect
to an average value along a substrate surface of at least 10 cm.sup.2.

30. A magnetron sputtering apparatus comprisinga) a magnetron sputter
source having a sputter target with a sputter surface and a magnet
arrangement, said magnet arrangement being coupled to a drive to be
cyclically moved along a plane parallel to said sputter surface;b) a
substrate conveyor arrangement for moving at least one substrate along
said sputter surface; andc) a modulation arrangement cyclically
modulating a total amount of material sputtered off said sputter surface,
said modulation arrangement being phase locked with said drive.

31. The apparatus of claim 30, wherein said drive comprises one of a
rotational pendular drive that generates rotational pendulum movement and
a rotational drive that generates a rotational movement ofsaid magnet
arrangement with respect to an axis that is perpendicular to said sputter
surface.

32. The apparatus of claim 30, wherein said modulation arrangement
modulates the amount of sputtered off material per time unit
simultaneously along the entire sputter surface.

33. The apparatus of claim 30, wherein said modulation arrangement
comprises at least one of a reactive gas flow and a working gas flow
adjusting member.

34. The apparatus of claim 30, wherein said modulation arrangement
comprises an adjusting member for an electrical feed ofsaid target.

35. The apparatus of claim 30, wherein said magnet arrangement is shaped
symmetrical to an axis which is parallel to said sputter surface.

36. The apparatus of claim 30, wherein said magnet arrangement is shaped
symmetrical with respect to two mutually perpendicular axes parallel to
said sputter surface.

37. The apparatus of claim 30, further comprising a gas inlet that is
positioned adjacent to said magnetron source, said gas inlet being
connected to a gas tank arrangement comprising a reactive gas.

38. The apparatus of claim 30, wherein said target comprises a circular
target.

39. The apparatus of claim 30, wherein said target is formed of a single
material.

40. The apparatus of claim 30, wherein there is direct sight communication
between said sputter surface and said substrate conveyor arrangement.

41. The apparatus of claim 30, further comprising a monitoring arrangement
that monitors a local distribution of material deposited on a substrate
at said substrate conveyor arrangement, an output ofsaid monitoring
arrangement being operationally connected to an input of a comparing
unit, a second input of said comparing unit being operationally connected
to an output of a setting unit, an output of said comparing unit being 1
operationally connected to a control input of an adjusting unit of said
modulation unit.

42. The apparatus of claim 30, wherein said conveyor arrangement is
operationally connected to a cyclical drive.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001]This is a continuation of U.S. patent application Ser. No.
10/530,994 filed Sep. 7, 2005 and now U.S. patent Ser. No. ______, which
was a 371 application on international application PCT/CH2003/000674
filed Oct. 15, 2003, which claims priority on U.S. provisional patent
application 60/418,542 filed Oct. 15, 2002, which priority is repeated
here and all three prior applications being incorporated here by
reference.

FIELD AND BACKGROUND OF THE INVENTION

[0002]The present invention concerns a procedure in accord with the
principal concept of the claims.

[0003]WO 00/71774 of the same applicant as of the present application,
discloses, that in a case of a sputter source, which has been
"operational point stabilized" and is used in a reactive coating process,
at which said source, a planar substrate, situated parallel to the
sputter surface, can be moved in a circular path relative to the sputter
surface to compensate for a so-called "stringy effect". The term "stringy
effect" is to be understood as an unequal apportionment of the quantity
of material deposited on the said substrate in the direction of the
movement of the substrate. This is essentially disturbing in that,
because of the circular path, and because of the planar state of the
substrate, different substrate zones build themselves parallel to the
sputter surface as the deposition experiences different distances of
separation and angular relationships with the sputter surface. The
different coating rates which evolve from the above, extending in the
direction of motion of the substrate, are compensated for in that,
synchronously with the substrate movement over the sputter surface, the
treatment atmosphere is modulated in accord with a given profile.

[0004]In addition, magnetron sputtering is known. In this process, by
means of the sputter surface, one or more, preferably self closing, loops
of tunnel shaped magnetic fields form from the sputter surface, aligning
themselves out of and within this said surface. Because of the electron
drop known in a magnetron-magnetic field interacting with an applied
electrical field, there arises in the area of the said tunnel shaped
magnetron magnetic field pattern, an increased density of plasma, which,
on its own, leads to an increased sputter rate in this zone. The sputter
rate achieved by means of magnetron sputtering is essentially greater
than sputtering which is not supported by a magnetic field. Because,
however, along the magnetron magnetic field pattern, an increased sputter
rate occurs, in the sputter surface eroded grooving appear, which are
generally known as a "race track" presentation. This so-called race track
then leads to a circumstance, wherein a poor usage of the sputter target
material results.

[0005]Primarily based on these grounds, one comes to the conviction, that
the magnetron magnetic field pattern, while the source is active, must be
moved above the sputter surface and thereby, to the greatest possible
extent, distribute an increased sputtered material deposition below the
said pattern and consequently over the entire sputter surface in the
given time. Thus, it can be additionally achieved, that, in a case of
reactive magnetron sputtering with a movable magnetic field pattern, an
essentially reduced poisoning of the target, that is to say, forming a
disturbed coating of target surface areas, which have poor electrical
conducting interbindings which are needed for a successful reactive
process. In the case of reactive coating processes, that is, the
production of a coherent layers, for example, starting from a metallic
target in the presence of a reactive process gas, possibly oxygen, for
the deposition of metal oxide layers, because of a mobile magnetron
magnetic field pattern, a uniform, cyclic erosion of the sputter surface
occurs, whereby a disturbance of the coating, here an oxide layer, is
considerably reduced. This action leads to increased process stability.
On this account, it is generally not necessary to provide an operational
point stabilization by control, where reactive magnetron sputtering with
a mobile magnetron magnetic field pattern is carried out.

[0006]Normally, the cyclic movement of the magnetron magnetic field
pattern along a sputter surface is realized in one or two dimensions.
Thus it becomes possible, for example, in the case of a long, rectangular
target, that a pattern which forms a closed loop can be cyclically moved
back and forth in the longitudinal direction of the target, whereby this
movement is cyclic in one dimension. Again, in the case of a target
arrangement which is extended into two dimensional directions, then the
magnetic field pattern is cyclically reciprocating in both directions,
which leads to a movement path of the magnetic field along the sputter
surface in accord with a Lissajous-figure. The cyclic magnetic field
pattern movement can be attained, especially in the case of round
targets, principally by means of a rotational movement, which can be
either in circle form or as an oscillating, pendular motion, which takes
place in relation to a vertical axis from the sputter surface. In this
operation, it is immediately obvious, that in regard to this said axis,
the magnetic field pattern must not be circular.

[0007]Magnetic field patterns which are rotational, are already known,
which are simply mirror-symmetric to an axis in a plane parallel to the
sputter surface. Such magnetic fields are, for example, in the form of
hearts, apples, kidney and the like as may be taught by the following
U.S. patents:

[0008]U.S. Pat. No. 4,995,958

[0009]U.S. Pat. No. 5,252,194

[0010]U.S. Pat. No. 6,024,843

[0011]U.S. Pat. No. 6,402,903.

[0012]Further, the shapes may be double mirror-symmetric in form, as seen
in the figure "8", in accord with U.S. Pat. No. 6,258,217, thus
mirror-symmetrical to two axes, which are perpendicular to one another in
the said plane.

[0013]In addition to the above, a process is known, of moving the
substrate, which is to be coated, during the coating procedure, along the
sputter surface with the mobile magnetron magnetic field pattern. This is
especially advantageous, for the so-called "Batch-Equipment", wherein
several, even a multiplicity of substrates are coated during one
equipment coating cycle.

[0014]The requirements of the local apportionment of the thickness of the
coating, that is to say, the requirements on the off-sputtered materials
along the substrate surface, are in many cases, very high. In the case of
optical coatings, for example, such as found in applications regarding
components for projection displays, it is necessary that coated
substrates have a layer-thickness apportionment, which deviates at the
most, 1% from the average thickness for an area of 1000 cm2, in
order to assure a favorable economic production of coatings consisting of
only few layers up to perhaps 50 layers. In the application of so coated
substrate for optical data transmission, then coating thickness
deviations of, at the most, 0.01% in reference to the average layer
thickness are demanded. In this case the produced surfaces would be at
the least, 10 cm2. In this latter case, onto such substrates, up to
more than 100 individual coatings may be laid in processes with durations
between 12 and 50 hours.

[0015]Fundamentally, the basics lie therein, in that by the use of a
magnetron source with a sputter surface, wherein a magnetron magnetic
field pattern is cyclically moved along a sputter surface, and substrate
is specifically distanced from the sputter surface and moved thereover,
one will gain the largest possible substrate surfaces having the smallest
possible deviations of the coating thickness--in the case of reactive
coating processes of the deposited quantity of the off-sputtered
materials--along the substrate surface. When we speak, in this
connection, of the "coated substrate surfaces", we mean the entire
combination of such surfaces of a plurality of batch-treated small
substrates or the surface of one large substrate.

[0016]We speak in the following in regard to the apportionment of the
coating thickness and understand, in this respect, the apportionment of
the quantity of off-sputtered materials onto the substrate surface for
reactive processes, which, in the case of said reactive processes, does
not have to depend on a linear correlation with the thickness of the
layer.

[0017]In order, that in the use of a round magnetron source having the
substrate movement as described, static components are inserted to reach
an acceptable coating thickness apportionment, presently, between the
motion path of the substrate and the sputter surface, which establish the
apportionment of the material flow between the sputter surface and the
substrate, these components are known as aperture orifices or "Shaper
Orifices". Normally, in this case, the said aperture orifices are
combined with the circular disk shaped sputter surfaces, and, as has been
mentioned, the magnetic field pattern cyclically moves along the sputter
surface by rotation about an axis vertically extending from the sputter
surface.

[0018]The provision of components of this type, such as the said shaper
orifices, does well to enable the achievement of layer thickness
apportionments on the mobile substrate with deviations from the average
of the layer thicknesses of less then 1%, but only when one takes into
consideration, the essential disadvantage, that by means of such
interposed components considerable quantities of sputtered material are
masked out before they reach the substrate, wherewith, at a uniform
sputter rate the coating rate is essentially reduced.

[0019]These components, which often must be matched to the currently
employed sputter sources, and upon each modification, especially the
magnetron magnetic field pattern and its motion must be set up anew and
optimized with the aid of iterated steps, while the coating process
itself produces a disturbed layering. Because of the considerable heating
of such components in the process space, layer tensions can arise, which,
for example, together with thermally conditioned shaping changes, such as
the distortion of such components, lead to a situation, in which the
mentioned disturbed layer can exfoliate and deposits on the substrate can
lead to coating defects.

SUMMARY OF THE INVENTION

[0020]Thus it is the purpose of the present invention, to propose a
procedure for the production of magnetron sputter coated substrate of the
kind described in the opening passages, as well as proposing equipment
designed for the said procedure, to achieve the result, that substrate
with essentially improved apportionment of sputtered off material is
deposited along the sputter coated surface with essentially reduced
material flow masking as compared to the heretofore attainable
apportionment with the described reduced masking.

[0021]This will be achieved with a production procedure of the type
mentioned in the introductory passages of this description, in that, in
accord with the wording of the characterizations of claim 1, the quantity
of material deposited per time unit on the substrate is cyclically
changed in conformity with the phase locking of the cyclical motion of
the magnetic field pattern.

[0022]So that the present invention can be immediately understood at this
place, its principle, as set forth in FIG. 1 will be explained.

[0023]In FIG. 1, the cross-hatched circle S depicts a position of a
magnetron sputter source on a sputter surface, at which position the
maximum sputter rate is generated. A position S of this nature
represents, accordingly, a section of the area of the magnetron magnetic
field pattern. Since, in the case of FIG. 1, the existing and here
concerned phenomena known to the invention are outlined schematically,
only this position S should be taken as representative of the increased
sputter rate in the area of the magnetron magnetic field pattern. By
means of the two dimensional cyclic motion shown here, namely, a cyclic
movement yz, and, at right angles thereto, a cyclic motion xz
would produce an elliptic movement path, along which the position S moves
itself above the sputter surface.

[0024]Above and along the sputter surface with the two dimensional, cyclic
movable position S, runs a substrate SU with a uniform speed v. If one
assumes, that the position S at a specific period proceeds from one
position, pos. m to the next position, pos. m+1--as is shown in FIG.
1--within equal times, then there is built upon the substrate SU, those
layers, the location of which are marked with a cross X. It is
immediately obvious, that upon the substrate SU, a cycloid path is being
followed.

[0025]Examination also shows, that the position S dwells for a longer
period in the flex points about XW than in the zero-transient points
XN. This has the result that in the edged or peripheral areas of the
substrate SU, a larger quantity of material of the released material is
deposited than in the central sections.

[0026]If one now makes use of the present invention on the base of the
theoretically presented relationships as shown in FIG. 1, and changes, by
means of the cyclic and phase locked per-time-unit relationship, the
quantity of material deposited on the substrate in such a manner, that
the said quantity is always diminished, when the position S lies on the
areas XW, and the said quantity is always increased, when the
position S crosses over the areas XN, then the achievement is, that
the said inhomogeneous apportionment of the coating materials laid down
upon the substrate SU in the y-direction is adjusted into a homogeneous
and desired apportionment.

[0027]In an advantageous embodiment of the invented production method, the
cyclic motion of the magnetron magnetic field pattern is made two
dimensional, preferably realized by means of a pendular or a circular
rotational movement about an axis perpendicular to the sputter surface,
which has the end result of curving in Lissajous figures.

[0028]Further, the cyclic motion of the magnetic field pattern need not be
in any case necessarily two-dimensional. If, for example, where a
longitudinally extended target is involved, the magnetic field pattern is
only cyclically moved in the said longitudinal extension of the sputter
surface on the longitudinal target and the substrate is displaced
perpendicularly to this movement. In this case, the said
inhomogeneosities of the deposition thicknesses on the substrate in the
direction of the target longitudinal extension, in accord with the
invention, can be compensated for by a cyclic change of the sputter rate
along with phase lock of the cyclical motion of the magnetic field
pattern.

[0029]It is quite possible, to bring about the cyclic change of the
material quantity laid down on the substrate along the sputter surface in
a localized manner. In a considerably more favorable embodiment, the
proposal is made, that changes in the deposited quantity of material can
be phase locked simultaneously in common with the cyclic motion of the
magnetic field pattern over the entire sputter surface.

DEFINITION

[0030]We understand in regard to two mutually phase locked cyclic signals,
two periodic signals, which, respectively, in accord with a fixed number
of periods of one of the signals, are again in the predetermined phase
relationship with one another. Seen within a given window of time, their
frequencies f1 and f2 differ from one another by a factor
corresponding to a rational number.

[0031]In a most advantageous manner, over the entire sputter surface a
deposited quantity of material can be simultaneously changed, in that the
sputter-power is changed.

[0032]Instead of, or rather in addition to, the change of the deposited
quantity of material by means of a change of the sputter power, it is
possible that the said quantity of material, localized or even over the
entire sputter surface can be changed, by an alteration in the reactive
gas flow and/or by adjusting the operational gas flow, such as, for
example, a flow of argon in the process space.

[0033]Beyond this, it is possible, and preferable, to have the sputter
surface consist uniformly of a single material for sputtering, such as of
one metal, a metal alloy or a metal composite. It is, however, further
possible, by the use of a multicomponent target, to have surface sections
of materials of differing sputtering characteristics.

[0034]If one again observes FIG. 1, again theoretically, it can be
recognized that the deposited quantity of material should then possess a
minimum, when the position S takes up a location XW on the substrate
SU. In this respect, it is understandable, that in a further approved
embodiment, the phase locked, cyclical change of the material quantity
can be realized by a curve in respect to the time, the frequency spectrum
of which has a dominant spectral line at the said double frequency in
regard to the frequency of the cyclic magnetic field pattern movement.

[0035]In an additional advantageous embodiment, it is also proposed, that,
the mentioned curve possesses a further dominant spectral line upon the
frequency of the cyclic magnetic field pattern motion. This becomes
particularly evident, when not, as is shown in FIG. 1, the substrate SU
moves linearly above the sputter surface, seen in FIG. 1 as a top view of
the sputter surface, but, in just such a top view, here drawn in
cross-hatching, the substrate SU moves preferably in a curved track, that
is, a circular path with a center of curvature outside of the sputter
surface.

[0036]In regard to the proposal cited immediately above, fundamentally,
where a two dimensional, cyclic motion of the cyclic magnetic field
pattern is concerned, that particular movement component is decisive,
which is perpendicular to the movement direction of the substrate, still
seen as in top view against the sputter surface. The cyclic movements of
the magnetic field differentiate themselves in FIG. 1 in the y- and the
x-axis. If the movement of the substrate is carried out with a component
in the x-direction, then, correspondingly what is decisive, is that the
cyclic magnetic field pattern motion must be in the y-direction for phase
locking with the cyclic change of the sputter rate.

[0037]In another advantageous embodiment of the present invention, the
magnetic field pattern is designed to be mirror-symmetric to an axis in
one plane, which plane is parallel to the sputter surface, or mirror
symmetric to two, mutually perpendicular such axes.

[0038]In an additional preferred embodiment, namely, for reactive magnetic
sputter coatings, a reactive gas is provided in the process space between
the sputter surface and substrate.

[0039]Although by no means compulsory, advantageously, additionally a
circular sputter surface can be employed, with simplifies the complete
assembly of the magnetron source.

[0040]In a further approved embodiment of the present invention, between
the sputter surface and the substrate none of the material-flow
disturbing components exists in relation to the aforementioned aperture
orifice.

[0041]Advantageously, the curve of the phase locked, cyclic change of the
material quantity deposited on the substrate is selected dependent upon
the relative motion between the substrate and the sputter surfaces and/or
dependent upon the shape of the magnetic field pattern and/or dependent
upon the cyclic magnetic field pattern movement.

[0042]During the operational life of the source targets, which define the
sputter surface, the geometry of the sputter surface undergoes change,
because of the erosion of sputter. This, in turn, gives rise, during said
operational life of the target, to a changing apportionment within a
cycle of the magnetic field pattern motion of the off-sputtered materials
from the sputter surface and therewith a changing of the apportionment of
the quantity of material carried to the substrate surface. Such a change
of the sputter characteristics at the source itself cannot be corrected
by means of provided static components such as the said aperture
orifices. Conversely, the present invention opens the possibility, to
take up just such phenomena regarding the apportionment of specified
substrate layer thicknesses, since, in accord with a further advantageous
embodiment of the invention, the procedure of the phase locked, cyclic
change is subjected to a time-change. With such a time based alteration
of the procedure of the phase locked cyclical change, for example, the
amplitude or the curve shape thereof, can be thoroughly controlled and
executed in accord with empirically based values by means of a given
process. In another advantageous embodiment, this is done in that one
measures the material apportionment as it has been immediately deposited
on the substrate as a "rule quantity". This said rule quantity is then
compared with a standard apportionment and then, in accord with the
direction of the comparison results, namely a "rule difference", the
procedure of the phase locked, cyclic change is presented as a standard
value, in a control circuit for the quantity of material distribution. In
this way, it becomes possible to automatically undertake a resulting
shift in material apportionment. In a completely different, but
favorable, embodiment of the invention, the substrate can be moved over
the sputter surface a plurality of times. This is done advantageously, in
that the substrate is guided cyclically over the sputter surface, which
can be in a regulated to and fro movement.

[0043]In a preferred manner, the substrate is linearly moved parallel to
the oppositely situated sputter surface. When this occurs, it can be
moved, in a first additional, advantageous way, in a plane parallel to
the sputter surface or in a second favorable manner, in which the
substrate is moved, again situated opposite to the sputter surface, not
linearly as before, but rather in an advantageously circular path.

[0044]If the substrate, planarly situated parallel to the opposing sputter
surface is linearly moved, then, favorably, and as explained above, in
each case the phase locked, cyclic alteration of the quantity of material
is carried out in a procedural run, the frequency spectrum of which
evidences a dominant spectral line in a case of a doubled frequency in
relation to the frequency of the cyclic magnetic field pattern motion.
This takes place, in both cases, first, if the substrate is moved in a
plane parallel to the sputter surface, and second, if the substrate,
aligned planarly parallel to the sputter surface, is moved non-linearly,
that is along the said circular path.

[0045]If now, the substrate, again planarly parallel to the sputter
surface, is moved non-linearly, preferably along the said circular path,
then it can be demonstrated, that additionally to the said quantity of
material deposited on the substrate by means of the cyclic motion of the
magnetic field pattern phase locked variation, then the said quantity of
material can be changed synchronously with the movement of the substrate,
as this is amply explained in WO 00/71774.

[0046]If the substrate motion is carried out, in a nonlinear manner, again
planarly parallel opposed to the sputter surface, in this case preferably
along a circular path with the radius of curvature being outside of the
sputter surface, then the course of the cyclic variation of the quantity
of material, over a time period, is formed with a dominant frequency
component both in a case of the double as well as an equal frequency, in
relation to the frequency of the cyclic patter motion. Although, in
addition, in accord with the present invention, the possibility exists of
achieving the striven for, desired layer thickness apportionment profile
on the substrate, it is also possible in a highly preferred manner to
realized on the substrates an optimized, homogenous layer thickness
apportionment. In this way, again advantageously, planar, magnetron
sputter coated substrates are produced.

[0047]A magnetron sputter coating apparatus in accord with the present
invention consists of a magnetron source and a cyclically driven magnet
arrangement underneath a sputter target, situated in a plane parallel to
the sputter surface, and consists further of a substrate transport
apparatus, by means of which a substrate is moved above the sputter
surface. This so defined magnetron coating apparatus then has a
modulation arrangement for the per-time-unit of sputtered quantity of
material from the said source, and this quantity is modulated cyclically
and with phase locked with the cyclic motion of the said magnet
arrangement.

[0048]Advantageous embodiments of the magnetron sputter coating apparatus
in accord with the present invention are specified in the claim.

BRIEF DESCRIPTION OF THE DRAWINGS

[0049]The invention is now explained, for example, with the aid of
Figures. These show in:

[0050]FIG. 1, schematically presented, and without claim on physical
exactness, the distinguishing relationships, which serve as a basis for
the present invention of a magnetron sputter source with a mobile
magnetron magnetic field pattern and moveable substrate,

[0051]FIG. 2, schematically and simplified, a first embodiment of the
invented method, that is to say, an invented apparatus,

[0052]FIG. 3, in a presentation analogous to that of FIG. 2, a preferred
embodiment, as of the present day, of the invented method, that is to
say, of an invented apparatus,

[0053]FIG. 4, a plan view, of an advantageously employed rounded magnetron
source within the bounds of the invention, with various paths of motion
corresponding to the present invention, of a substrate as a basis for a
consideration of the path-specific optimized design of the present
invention,

[0055]FIG. 6, schematically, and highly simplified, an inline magnetron
sputter coating apparatus, whereby the substrate, mobile in relation to
the said source is realized, the said mobile substrate being as presented
in FIG. 4,

[0056]FIG. 7, once again schematically and highly simplified, an
apparatus, wherein substrates traveling on a circular path are moved past
the source in accord with second movement-method presented in FIG. 4,

[0057]FIG. 8 and FIG. 9,

[0058]layer thickness apportionments on the substrate, accruing deposited
material in relation to their direction of motion, without any
compensation,

[0059](a) with, as in the known manner, a provided aperture orifice,

[0060](b and c) realized with the present invention, and in

[0061]FIG. 10, an additional type of the relative motion between substrate
and the source.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0062]FIG. 2, simplified and schematic, is shown a first embodiment of an
invented magnetron sputter coating apparatus, i.e., a first variant of
the method of production in accord with the present invention.

[0063]A target 1, advantageously of one piece and of a material M or, one
or two pieces (note dotted lines) from respectively the materials
M1, M2, . . . A magnetron sputter source, not presented in
details, is fed by means of an electrical generator arrangement 3 in
reference to a (not shown) anode of the said source. This feed is
normally DC, if necessary both with DC and AC or only with AC, with the
current in the high frequency area Rf. Thereby, the schematically
drawn in electrical field E, which was presented in FIG. 1, is shown in
the known means and way. Beneath the target 1 is provided a magnet
arrangement 5, the magnetic field of which penetrates through the target
1 with field lines which protrude from and reenter into the sputter
surface 7. The field lines H form a field pattern 9 in the shape of a
closed, tunnel-like loop. The magnetron magnetic field pattern, in a
known manner, leads commonly with the electrical field leads to a marked
plasma density increase in the area of the magnetic field pattern 9 with
a therewith resulting increase of the sputter rate. The magnet
arrangement 5 generates in most cases, as already mentioned, the magnetic
field pattern 9 on the sputter surface 7, which field then appears as
closed loops.

[0064]As FIG. 1 shows further, with (not depicted here) driving means, the
magnet arrangement 5 moves along the target 1 in a back and forth manner,
in at least in the y-direction in accord with FIG. 1, this being a cyclic
movement, as is indicated by the double arrow My. With the magnet
arrangement 5 being underneath the target 1, the magnetic field pattern 9
moves uniformly along the sputter surface 7.

[0065]Distanced from the sputter surface 7, a substrate 11 is moved past
said sputter surface, doing this with at least a motion component
mx, which is perpendicular to the magnetic arrangement 5 and thereby
perpendicular to the magnetic field pattern 9. In accord with the
fundamental principle of the present invention, the rate of the materials
sputtered from the said sputter surface 7 changes cyclically in accord
with phase locking with the cyclic movement My of the magnet
arrangement 5. In other words, the magnetic field pattern 9 is modulated.
These said changes can be realized with the embodiment of FIG. 1, in that
between the magnetic arrangement 5 and the sputter surface 7 in the
motion direction My of the magnet arrangement 5, the magnetic
resistance of the penetrating power (punch-through) between the magnet
arrangement 5 and the sputter surface 7 locally varies or is locally
modulated. As is schematically depicted in FIG. 1, it is possible to
bring these changes about by adding locally increasing material inserts
13 to the magnetic resistance of the target 1, whereby, along the sputter
surface 7, the field strength H of the magnetic field pattern 9 will be
locally modulated, as will the thereto associated sputter rate. This
opens for the expert additional possibilities of modulating the sputter
rate locally and in phase locking with cyclic motion of the magnetic
arrangement 5. Among these possibilities would be, modulating the sputter
rate: [0066]by provision of electro magnets on the magnet arrangement
5, [0067]by mechanical displacement of individual magnets of the said
magnet arrangement 5, [0068]by modulation of the separating distance
between the magnet arrangement 5 and target 1, and the like.

[0069]Fundamentally, in the case of a procedure based on FIG. 1, the
sputter rate along the sputter surface 7 is thus locally modulated.

[0070]In FIG. 3 is a presentation, showing, analogously to FIG. 2, an
additional fundamental embodiment of the present invention, which
embodiment, at least now, can be clearly set forth. Having at hand the
procedures and components of FIG. 2, the same are depicted again in FIG.
3 using the same reference numbers, and need not be described once again.
As is illustrated in FIG. 3, the movement My of the magnet
arrangement 5 is effected by a drive 15. The electrical generator
assembly 3 for the target 1 has a control entry (or a modulation entry)
S3. An operational default 17 of the method, the output A17 of
which, is in active connection with the control entry S3, produces a
cyclic, periodic modulation signal for the generator assembly 3 with a
specified, preselected course of operational running. If one designates
the cyclic frequency of the motion My of the magnetic arrangement 5
and therewith, that of the magnetic field pattern 9 with f1, then
the frequency f2 of the periodic control signal, which is produced
at the unit 17, is being selected as nf1, where n is a rational
number. The periodic control signal of frequency f2, which is
conducted to the control input entry S3, is phase locked with the
cyclic movement My of the magnet arrangement 5 with the frequency
f1. This means that the phase position of the control signal, in
reference to the cyclic movement my, is respectively equal to a
given number n of periods of the cyclic control signal. In this respect,
there exists an entry of the default unit 17 accommodating the mechanical
outlet A17 of the drive 15 or, and preferentially, an active
connection with the electrical entry E15 of the drive 15, as is
schematically illustrated, this being done advantageously by means of an
adjustable phase presetting unit 18. At the unit 17 are provided,
advantageously, additional inlets S17, onto which values of the
cyclic control signal curve, especially frequency f2, can be
adjusted as to a curve shape with the amplitude and the like.

[0071]As shown in FIG. 3, again presented schematically and in dotted
lines, it is possible, changes can be made, so that instead of, or in
addition to, the advantageous variation of the sputter capacity, by means
of the generator assembly 3, phase locked by means of phase preset unit
18, a reactive gas Gr and/or a working gas GA such as argon can
be fed into the reaction space between the sputter surface 7 and the
substrate 11. The change can, in this respect, be made on a wide spread
basis over the entire sputter surface 7, or locally along predetermined
areas of the said sputter surface 7.

[0072]Differing from the embodiment in accord with FIG. 2, in the case of
the embodiment following that of FIG. 3, which is preferred today, the
sputter rate on the sputter surface 7, which is phase locked with the
cyclic motion of the magnet arrangement 5, is not locally changed, but
rather the entire existing sputter rate at the sputter surface 7, phase
locked with the magnet arrangement motion My, is changed.

[0073]In FIG. 4, schematically shown, and in top view, is a
round-magnetron sputter source 21, which is both in keeping with the
present invention and can be advantageously employed. Illustrated is the
target 23 thereof, i.e., the sputter surface of the magnetic field
pattern 9' and this is drawn in dotted lines thereon. The magnet
arrangement 25 is designed in the here presented top view, mirror image
symmetrically to an axis which is situated parallel to the said sputter
surface of the target 23 and the said arrangement is cardioid is shape.
The reference number 27 designates schematically the substrate which is
movable, in accord with the invention, in the x-direction. The cyclic
movement of the magnet arrangement, as located in FIGS. 2, 3 is, in this
case, here in an advantageous manner, realized as a two dimensional
cyclic movement, with the movement components My and Mx running
at the same frequency. This cyclic, two dimensional motion is
advantageously, and also as presented in FIG. 4, effected by a rotation
of the magnet arrangement 25 about the axis 24.

[0074]Obviously, it is possible, if required, instead of a circular
rotation, to employ a rotating pendulous motion. In addition, instead of
the presented single axle mirror symmetrical magnet arrangement 25,
another form of the magnet arrangement can be used. Especially is it
possible, as has already been mention in the introductory passages to
consider a double axis, mirror symmetrical magnet arrangement, for
instance in the form of the numeral "8" with a central rotation axis 24,
for example, this being the center of possibly also a kidney shaped unit.

[0075]In FIG. 5, the round magnetron sputter source, as per FIG. 4, is
schematically shown in cross-section, wherein the reference number 29
designates the mounting location of a conventional aperture orifice, this
being indicated by dotted lines. In regard to this, it should be
emphasized, that in accord with the present invention, only under the
greatest considerations, would be the installation of a designed
aperture, which would allow masking of the sputtered off materials from
the sputter surface to be essentially much less than the conventionally
installed apertures. In other words, in accord with the present
invention, the required layer deposit thicknesses can be attained
entirely without the provision of such components.

[0076]Advantageously, the substrate 27 can be passed by the source 21 many
times, if this is in a direction which remains unchanged, or if this is a
back and forth motion.

[0077]As has already been mentioned, the modulation curve form, which is
used in accord with the invention, modulates the sputter rate. The said
sputter rate is phase locked with the magnet arrangement-cyclic motion.
The sputter rate is that deposited quantity of material during any given
time period and is dependent upon the shape of the magnet arrangement and
its motion dynamics, and further dependent upon the moving path and
dynamic of the substrate motion. For example, there is presented in the
following, three cases which will be examined. The first and second cases
are found in the FIGS. 4, 5 wherein the substrate 27 is moved in a plane
parallel to the sputter surface of the target 23. The said movement is
linear in respect to the dotted path A-B or non linear in accord with the
alternate path A-B', thereby advantageously on a circular path about a
(not shown) center Z which lies outside of the sputter surface of the
target 23. The third case comprises a movement of the substrate 27 upon a
linear path, such as A-B is, as a rule, given in the case of so-called
inline-coating equipment. Such an in-line coating equipment example is
shown in FIG. 6. The substrate lies, in this case, on a substrate carrier
and would be, as though it were on a running belt, passed one or more
times, preferably the latter, linearly beneath the sputter source. In the
case of the previous procedure, a provided aperture orifice would have
been installed at location 29, if the installation were not in accord
with the present invention.

[0078]FIG. 7, schematically, shows how the non-linear motion path A-B', as
per FIG. 4, for example, is carried out. In this case, the substrate 27
is on a disk shaped or a domed substrate carrier 30', with a center of
rotation z outside of the sputter surface of the source 21. In FIG. 7,
the reference number 29'' provides the location, where, in accord with
up-to-now technology, an aperture orifice must be installed.

[0079]In accord with FIG. 4, the substrate 27 possesses a range with an
extension in the y-direction from y1 to y2, which, with
specified layer thickness apportionment, should be, as much as possible,
coated with a homogeneous layer. In accord with the present invention,
with a modulation of the sputter capacity, the sputter rate for each
position of the rotating magnet arrangement 25 is directly influenced, in
order that, by an appropriate selection of the modulation curve, a
homogenization of the resulting layer thickness on the substrate can be
attained, without the installation of an aperture orifice or, at the
most, with the installation of an aperture orifice with essentially less
sputter masking properties than would be the case with conventional
apertures.

[0080]As has already been made plain in FIG. 1, confirmation has been
made, that in the case of the linear movement A-B, or for that matter,
where any linear motion component is concerned, it is of advantage to
select the basic modulation frequency in accord with f2 of FIG. 3 at
the doubled rotational frequency f1 of the magnet arrangement 25, 5
under such circumstances, that no additional asymmetries need be
corrected. In this way, a modulation curve form is advantageously chosen
at the default unit 17 (FIG. 3), which has in its frequency spectrum at
2f1 at a transcending spectral amplitude. The rotation frequency,
i.e. the cyclic frequency in accord with f1 of the magnet
arrangement 25, 5 must be set so high, that during the movement of the
substrate 27, 11 as it passes the source, the magnet arrangement 25, 5
runs through a plurality of cycles, which is assured by a corresponding
increase of the magnet arrangement cyclic frequency, i.e., a slowing of
the substrate velocity. Typical cyclic frequencies of the movement
My, again as shown in FIG. 3, or in other words, the rotation in
accord with FIG. 4, lie in that Hz range generally between 0.1 and 10 Hz
and the movement of the substrate 27, 5, as it passes the sputter source
endures for several seconds, even when the substrate is passed by the
magnetron sputter source only once. In the case of a multipassage of the
substrate past the sputter surface, the substrate motion can be increased
in its speed. In any case, care must be taken here, in that the cycle, at
which the substrate passes the sputter surface, is made asynchronous to
the cycle of the magnet arrangement motion. In the case of a cycle of the
substrate movement in synchrony with that of magnet arrangement, it
becomes necessary, in some instances, that additional manipulation of the
sputter rate be employed, which said rate is synchronized with the
substrate movement.

[0081]FIG. 8 presents the simulated curve of the coating layer thickness
apportionment on a plane substrate, which, in accord with FIG. 4, has
been moved over the sputter surface a plurality of times along motion
path A-B. In this drawing, D designates the diameter of the circular
sputter surface, and the positions y1 and y2 show the
corresponding locations on the substrate 27 of FIG. 4. The y-direction
corresponds to the y-direction on the substrate, in accord with FIG. 4,
that is to say, the y-direction in accord with the FIGS. 2, 3. Curve (a)
shows the layer thickness, if the sputter coating apparatus is used
without the invented sputter-rate modulation and without use of the
aperture orifice. The curve (b) exhibits, again without use of the
invented sputter-rate modulation, but with the provision of an aperture
orifice 29', as this is shown in FIG. 8. The curve (c) designates the
result in the case of the invented employment of the cyclic variation,
i.e., modulation, of the sputter rate, in accord with the phase locked
cyclic movement of the magnet arrangement, as this is also brought about
as per FIGS. 3, 4. A modulation curve was used, the spectrum of which has
basically a specifically harmonic, superimposed spectral line. The
simulated curves in accord with FIG. 8 have essentially proven themselves
in the meantime in practice. By the omission of the aperture orifice 29'
and the use of measures in accord with the present invention,
essentially, all of the material set free from the sputter surface
reaches the substrate, which leads to a significantly increased coating
rate, along with shorter coating times and greater productivity.
According to FIG. 8, the coating rate is increased, about some 18%. This
is accomplished during a uniform, average electrical consumption at the
magnetron source and beyond this, especially with a method in accord with
FIG. 4, showing efficient use of target material, all leading to better
operational life of the coating equipment. By the use of an aperture
orifice, it is possible, that the loss relative to the coating rate
cannot be simply compensated by an increase of the applied electrical
load, because the maximum usable electric sputter load at the target is
generally limited by the efficiency of the provided target cooling.

[0082]In a case of a reactive magnetron sputter coating apparatus process,
wherein (not shown) in all executable forms of the present invention,
between the magnetron sputter source and the substrate, a reactive gas is
released, there arises accordingly, deficiencies in the layer quality due
to excessive source loading. Because of such excessive loading, the
reaction process of the material set free changes with the reactive gas,
which in turn leads to stoichiometric changes of the deposited material.
In this case, it is possible, for example, that the optical absorption in
one or more layers, because of the said changed stoichiometry, is
increased in a disturbing amount.

[0083]The second of the above mentioned three substrate movement types is
as shown in FIG. 4, i.e., non-linear, and specially along a circular path
AB'. The path of movement of the substrate, possesses in this situation,
as is obvious, both a movement component Mx, that is in the
direction of A-B as well as a movement component perpendicular thereto,
namely My. An asymmetric layer thickness apportionment arises
therefrom, in relation to the y-extension of the substrate. This is made
clear by an observation of FIG. 7. In the y-direction, displaced
substrate areas are moved with different velocities over areas of
different lengths on the sputter surface in relation to the magnetron
sputter sources extending along axis z. The corresponding results evolved
in FIG. 8 for this case are presented in FIG. 9. The curve of the layer
thickness upon the coating with one arrangement, as this is shown in
FIGS. 4, 2, without the use of the invented sputter rate modulation and
without the use of an aperture orifice is shown in (a). In order to
compensate for the strongly inhomogeneous apportionment (a) with an
aperture orifice 29'', it is necessary that the latter be appropriately
asymmetrically shaped. The curve of the coating with the provided
aperture orifice 29'', but without the use of the invented sputter rate
modulation, is indicated by the curve (b). The curve (c) shows the layer
thickness apportionment with the use of the invented sputter rate
modulation. In this situation, analogous observations regarding FIG. 8, a
modulated, cyclic curve was chosen, which, first, because of the
substrate motion in the x-direction corresponding to Mx of FIG. 4,
with the doubled frequency of the cyclic magnetic arrangement movement,
its frequency spectrum exhibits a predominate spectral amplitude. Second,
however, in order to consider the rate differences due to the different
movement radii of the different substrate units in the y-direction in
accord with discussion of FIG. 7, a further predominate spectral
amplitude can be attained, wherein the frequency equals the frequency of
the cyclic magnet arrangement motion.

[0084]Employed is a simple, mirror symmetric magnet arrangement with an
offset axis of rotation in accord with FIG. 4, since, in the case of a
double-axis symmetrical magnet arrangement, for example in the form of a
figure "8" with a sputter rate modulation with predominate modulation
frequency, which corresponds to that of the magnet arrangement motion, no
asymmetry in the sputter rate and the therewith associated coating rate
can be achieved. If a simple mirror symmetric magnet system in accord
with FIG. 4 is employed, then it becomes possible to reach the necessary
asymmetry with the design of this magnet system, which carries out the
remaining homogenizing of the layer thickness apportionment in the manner
of FIG. 8, that is to say, with linear movement components in the
direction of A-B in accord with FIG. 4, with the aid of the sputter rate
modulation, holding to the doubled frequency, based on the frequency of
the cyclic magnet arrangement motion.

[0085]Both in the case of a linear substrate path parallel to the sputter
surface, as well as in the case of a curved substrate path, again
parallel to the substrate surface it is possible, as has been described,
with the aid of the sputter rate modulation, especially realized by means
of sputter capacity modulation in accord with FIG. 3, to achieve a very
good layer thickness apportionment, without the necessity, that aperture
orifices must be installed. Thereby, an optimization of the layer
thickness apportionment is enabled by means of an external variable
process parameter, namely the electrical sputter loading. Essentially for
the optimal functioning of the invented dynamic layer thickness
apportionment correction measures, the speed, that is, the rate of
change, with which the electrical load, which is conducted to the source,
can be altered. With the present day, commercially obtainable
power-supplies, an additional possibility is, to modulate the output
loading in the small signal type, that is, typically plus or minus 1 to
10% about the static operational point loading, with frequencies up to
the range of above 100 Hz without significant signal inrush. In this way,
even complex modulation curve shapes with basic frequencies in the range
of more than 10 Hz and significant high spectral portions can be made
with considerable exactness and without essential phase slipping. This is
important for a precise running of the modulation and the phase locking
with the cyclic magnet arrangement motion.

[0086]The greater coating rate, i.e. sputter rate, can also, in accord
with the invention, be attained in a case of a reactive magnetron sputter
process. The relevant time-constant, (which lies in a range exceeding ca.
100 msec) for the stability of the reactive process is dependent upon the
process, for example, dependent upon the relative gas pressure, sputter
rate, chamber geometry, vacuum pump characteristics and the like. In the
case of a cycle frequency, that is, the rotational frequency, of the
magnet arrangement 25, 5, as seen in FIGS. 4, 3, of a few Hz, the
relevant time-constant τ=1/(2 τ f) for the changing of the
coating rate, for example, the sputter rate lies definitely under this
cited 100 msec, whereby the influencing of the reactive process is only
minimal. In other words, the reactive process is normally too sluggish,
than that it can be particularly disturbed by the invented, actively
used, sputter rate modulation.

[0087]FIG. 10 shows, schematically, the third case of the substrate
motion, in accord with which, possibly additional to the formulation of
the movement path, as presented in FIG. 4, the movement path, seen in a
direction parallel to the sputter surface of the source 21, is curved,
advantageously in accord with a circular arc. In this case, besides the
already explained sputter rate, modulation course, which relates to the
path A-B or A-B', this phase locked with the cyclic motion of the magnet
arrangement--as this is explained in WO 00/71774 is--the sputter rate
changes with an additional modulation, now, however, synchronized with
the substrate movement, in order to even out the stringy effect mentioned
in the introductory passages.

[0088]The optimization of the layer thickness apportionment in accord with
the present invention, and especially by means of the externally
available process parameter "sputter loading" enables also a matching to
the actual erosion condition of the target in the concept of a placement
of the modulation curve shape onto currently appearing relationships. In
this way, it is possible that the remainder dependency of the layer
thickness apportionment by means of the operational life of the target
can easily be eliminated. Because the influencing of the apportionment by
means of the changing, that is to say, because of the modulation of the
sputter rate, especially in a case wherein modulation of the sputter
loading is done practically without delay and enables a partitioning by
in-situ-control. In this way, with the aid of an appropriate in-situ
measurement system the presently effective layer thickness apportionment
at the moment is done, for example, through the so called broad-band
spectral monitoring and the measurement result can be used as a
control-value in a regulation circuit for the control of the layer
thickness apportionment.

[0089]This is presented schematically and in dotted lines in FIG. 3. By
means of the measurement system 40 for layer thickness in-situ, the
instantaneous layer thickness apportionment on the substrate 11 is
determined. At a comparator unit 42, the measured apportionment is
compared with an existing memory statement 44 of a specified
apportionment, which was input in the form of, so to speak, a table. The
output of the comparator 42, with the control difference Δ, is
actively bound at the control input S17 of the modulation default
unit 17, and at this location, the course of the sputter rate modulation
in the function of the control difference Δ which appears at the
output of the comparator 42 is held up to such a time, until the measured
layer thickness apportionment no longer deviates from the specified
apportionment W, as this difference is given within the allowable
remaining control deviation.

[0090]Even if greatly emphasized in the course of the description of the
present invention, attention is directed to the achieving of an
optimized, homogeneous layer thickness apportionment on the produced
substrates. It is, without further consideration, obvious, that by means
of an appropriate design of the sputter rate modulation, determination
may be made as to what kind of a basic frequency, curve characteristic,
and phase situation should be properly associated with the movement cycle
of the magnet arrangement. Other desirable layer thickness apportionments
on the substrate can be attained, when seen in a direction transverse to
the motion direction of the substrate which substrate is in the form of a
plane and is parallel to the sputter surface.